How to log queries using Entity Framework 7?

Question

I am using Entity Framework 7 on the nightly build channel (right now I\'m using version EntityFramework.7.0.0-beta2-11524) and I\'m trying to log the queries that EF genera

Answer 1

I struggled with all the above answers as the EF bits kept changing, so the code wouldn't compile. As of today (19Feb2016) with EF7.0.0-rc1-final (Prerelease) and SQLite, here's what works for me:

From the EF7 documentation:

using System;
using System.IO;
using Microsoft.Extensions.Logging;

namespace EFLogging
{
    public class EFLoggerProvider : ILoggerProvider
    {
        public ILogger CreateLogger(string categoryName)
        {
            return new EFLogger();
        }

        public void Dispose()
        {
            // N/A
        }

        private class EFLogger : ILogger
        {
            public IDisposable BeginScopeImpl(object state)
            {
                return null;
            }

            public bool IsEnabled(LogLevel logLevel)
            {
                return true;
            }

            public void Log(LogLevel logLevel, int eventId, object state, Exception exception, Func formatter)
            {
                File.AppendAllText(@".\EF.LOG", formatter(state, exception));
                Console.WriteLine(formatter(state, exception));
            }
        }
    }
}

Using some ideas above and the EF7 Docs:

using System;
using Microsoft.Data.Entity;
using Microsoft.Data.Entity.Infrastructure;
using Microsoft.Extensions.DependencyInjection;  // Add this to EF7 docs code
using Microsoft.Extensions.Logging;

namespace DataAccessLayer
{
    public static class DbContextExtensions
    {
        public static void LogToConsole(this DbContext context)
        {
            var serviceProvider = context.GetInfrastructure();
            var loggerFactory = serviceProvider.GetService();
            loggerFactory.AddProvider(new EFLoggerProvider(logLevel));
        }
    }
}

EDIT: @jnm2 pointed out if you add "using Microsoft.Extensions.DependencyInjection", the EF7 docs ARE correct. Thanks!

And finally, in my App.OnStartup method:

using (var db = new MyDbContext())
{
    db.LogToConsole();
}

This code will create a log file and also output logging info to the Visual Studio output window. I hope this helps -- I'm sure in a few weeks, the bits will change again.